It’s the usual lobbying game with every contender trying to avoid moving as much as possible.
But the law does not enforce how this is to be implemented, just that, it’s up to the companies
(the famous “free market” and “technology openness” our 3-Pünktchen-Partei keeps asking for).
There’s several options. You can bring your own smart meter like aWATTar does with Discovergy meters or add your own device to read a (non-smart) digital meter like Tibber does with their “Pulse”. I’ve implemented both of them in my system so it is already available to customers to benefit from this today. And I’m sure there will be more ways by the time it applies.
… and even with a Ferraris meter you can take part in the game: Tibber bills monthly according to standard load profile (Standardlastprofil) and hourly energy rates - other energy providers might jump on the waggon.
The first two columns are obvious, it’s the month and our consumption in kWh on that month
The third column is the monthly average price in Finland.
The fourth column is showing what our actual average has been on that month compared to the market average. In other words, we have been consuming most of our electricity during hours that are cheaper that the monthly average.
The consumption factor is the difference between the market avg and our actual avg. For example, in 2022-08 market avg was 32,4 c/kWh and our actual avg was 22,5 c/kWh so the “consumption factor” was -9.9 c/kWh.
Then to the original question “how much money have you saved”. It of course depends on where do you compare to, so I calculated a couple of scenarios.
Reference cost 1 has the following assumptions:
I would have a dynamic tariff / spot price contract with 0,38 c/kWh margin (this is the cheapest margin that I was able to find today when I quick compared the dealers)
I would not have any scheduling for the consumption so our monthly average would be 20% above the market average because most of the consumption would happen during the day when the spot prices are usually above the monthly average.
I have no idea if this 20% is the correct factor for this since I’ve never had a spot price contract without doing schedule optimization.
Reference cost 2 has the following assumptions:
I would have a dynamic tariff / spot price contract with 0,38 c/kWh margin
Our consumption is optimized to the cheapest hours like it has been since last summer
Our actual cost is with the Väre Välkky contract type
With this contract type I share the price risk with the dealer so that our price is 14,8 c/kWh +/- consumption factor
In other words, if we consume electricity during an hour where the spot price is below the monthly market average, we get discount for the whole month’s consumption. If we consume electricity during an hour where the spot price is above the monthly average, our price / kWh for the whole month increases.
Väre was the only company having this contract type last summer but now also Helen has this same contract type (Helen Fiksusähkö) and Fortum has it (Fortum Duo)
So how much have we saved… Compared to reference cost 1, our cumulative saving so far is 762 EUR. Compared to reference cost 2, we are still on the saving side by 51 EUR.
Now that the prices are back to normalish, we will most probably end up losing against reference cost 2 in the 24 month contract period that we have, but I consider that as the price of the “insurance” that we decided to take last summer when the hell broke loose in the energy market. When the 24 month contract ends in a year from now, we will for sure go to a pure spot price contract and continue the schedule optimization.
Edit: I forgot to mention that we got an electric vehicle in 2023-02 so the consumption went up.
Edit 2: Table formatting
Edit 3: Fixed copy-paste error from May 2023
Another aspect to this cost savings is the durability of our ground source heat pump. Our heat pump is a traditional on/off compressor pump. In other words, it’s not a modern inverter pump where the pump is able to adjust its speed, our heat pump is either ON or it’s OFF.
Based on the discussions on heat pump forums, some people are saying that the compressors of on/off pumps will last about 100 000 compressor starts before they break down. Between 2020-01-29 and 2022-05-20 our compressor had a massive 22 808 compressor starts, which is 28 compressor starts per day!
The pump had been running on full automation. The biggest contributor to this massive number of compressor starts turned out to be a water pump that circulates domestic hot water so that when you open the tap, you’ll get hot water immediately. The pump had been running 24/7 for 2,5 years and the circulation was causing the low sensor of the domestic hot water tank to fall below the lower threshold every 45 minutes or so. When I realized this, I immediately bought a mechanical timer that started to cut the power from the circulation pump so that it was only circulating the water when we need hot water. This helped a lot, but I then later automated this to openHab-controlled relay so that I was able to automate it more elegantly.
Anyway, here are the stats for the compressor starts, average number of heating hours per day and average number of domestic hot water heating per day. Unfortunately I don’t have data for the last couple of days of March and the almost whole month of April this year because I forgot to enable logging when I plugged the USB stick back to the heat pump
Month
Compressor starts
Starts / day
Heating / day (h)
DHW / day (h)
COP / heating
COP / DHW
2022-08
24
0,8
0
0:37
n/a
3,3
2022-09
67
2,3
2:12
0:37
5,5
3,3
2022-10
76
2,5
4:54
0:42
5,3
3,3
2022-11
55
1,8
5:57
0:49
5,4
3,5
2022-12
68
2,2
8:45
1:01
5,4
3,6
2023-01
63
2,1
8:14
0:51
5,3
3,5
2023-02
53
1,9
8:30
0:39
5,3
3,5
2023-03
n/a
1,6
6:44
0:45
5,4
3,5
2023-04
n/a
2023-05
38
1,2
0:46
0:43
5,5
3,1
The number of compressor starts is now on very low numbers so I hope my compressor will have many years ahead. For most of the winter I was able to heat the house at one or max two heating periods when the prices were at lowest on that day. Only on the coldest days had we use three heating periods per day so that the house doesn’t cool too much between the heating periods. This concept of dividing the day to 1-N heating periods is thoroughly discussed between myself and @mstormi in the thread of my solution, the link is in the previous comment above.
I think the monthly Tibber fee (3.99 EUR/month in Germany) is based on the average savings that an average household (without PV/EV) can achieve by shifting consumption to cheap hours.
Now that we’re on the summer months and we don’t need to heat the houses, the heating of domestic hot water plays a huge role here. As we discussed separately before, you only have 180 l capacity and when it is being consumed, you pretty much need to heat more of it regardless of the spot prices because otherwise you will risk running out of hot water and the WAF factor will suffer.
Our house has 180 + 300 liters of hot water so we can easily schedule the heating to the cheapest hours and for the 300 liter tank, we can even skip entire days if needed (unless we use the bathtub).
Because we can schedule the heating of domestic hot water, our May was 34% (-1.1 c/kWh) below the average market price (you were 1% below). In June, the monthly average on June 1-6 is 1.54 c/kWh. We are at 0.94 c/kWh average so far i.e. 0.6 c/kWh below average, or 39% below.
-50 c/kWh is a lot, I just wish we would have those prices here in Finland.
Meanwhile my electricity bill for June came in:
Consumption: 498,31 kWh
Price: 4,89 c/kWh
Cost: 29,25 € including tax 24%, margin 0,25c/kWh and monthly fee 4,9€
Average spot price in June: 5,37 c/kWh
Savings: 9,04% below spot average
Savings: 50,2% below local energy company fixed price
We currently have diswasher, washing machine and ground source heat pump under spot price optimisation.
Yeah. I don’t have time to calculate the exact price diffs like above, but here are the stats from this June onwards.
June 2023
Consumption: 636 kWh
Spot market avg: 5,37 c/kWh
Our actual avg: 4,65 c/kWh
Consumption factor: -0,72 c/kWh (-13%)
We paid with Välkky 14,8 - 0,72 = 14,08 c/kWh
July 2023
Consumption: 596 kWh
Spot market avg: 4,08 c/kWh
Our actual avg: 2,86 c/kWh
Consumption factor: -1,22 c/kWh (-30%)
We paid with Välkky 14,8 - 1,22 = 13,58 c/kWh
August 2023
Consumption: 704 kWh
Spot market avg: 8,23 c/kWh
Our actual avg: 5,06 c/kWh
Consumption factor: -3,16 c/kWh (-30%)
We paid with Välkky 8,88 - 3,16 = 5,72 c/kWh
We had 12 months left of the 14,8 c/kWh Välkky but Väre introduced a new 12 month agreement and was selling it with 8.88 c/kWh. We were able to change our previous agreement to this new price, which was nice
Sep 2023
Consumption: 672 kWh
Spot market avg: 4,08 c/kWh
Our actual avg: 2,27 c/kWh
Consumption factor: -1,81 c/kWh (-44%)
We paid with Välkky 8,88 - 1,81 = 7,07 c/kWh
October 2023 so far
Consumption so far 1004 kWh
Market price avg so far is 3,54 c/kWh
Our avg so far is 1,41 c/kWh
Consumption factor being -2,13 c/kWh at the moment (-60%, all time record in percentage values)
I will change back to a spot price contract for sure next summer when the remaining fixed period contract ends for us.
Not that there would be anything wrong with these consumption factor agreements (Väre Välkky, Helen Fiksusähkö, Fortum Duo and others). I honestly believe that this is the future because it’s a shared-risk model between the seller and the buyer which raises the awareness of the consumers. And this awareness we will most definitely need as more and more of the energy production is dependent on weather conditions. And what I consider even more important, the awareness is good for the environment and the future of our planet. If you’re a subscriber to Helsingin Sanomat, you can read more about my thoughts at https://www.hs.fi/mielipide/art-2000008978175.html (it’s from last year August).
Having said this, a pure spot price agreement is going to beat these consumption factor agreements by a big margin if you are able to schedule your consumption like we can. With a spot price contract, our October would be only 1,41 c/kWh so far and September would have been 2,27 c/kWh. You just can’t get these kind of price levels with any kind of fixed or semi-fixed agreement.
If we look at what are the prices in the futuurimarkkina (whatever that is in English) for the next 12 months, the weighted average price is currently being traded at 7.62 c/kWh. Weighted average is calculated so that 65% of the annual energy consumption takes place in the heating season and 35% during the summer.
Väre sells 12 month Välkky at 9.70 c/kWh +/- consumption factor at the moment, Helen is at 9.90 c/kWh. So their margin (in the base price) is a bit more than 2.0 c/kWh with these agreement types.
Based on the past experience and the data shown above, our household can be quite confident that we can beat the average spot price by 30%. So for us the next 12 months should be something like 5,33 c/kWh. This would mean that our consumption factor would be around 7.62 - 5.33 = -2.29 c/kWh.
We would need to get -4.0 c/kWh consumption factor to get even with a pure spot price agreement but with the estimation above, we can reach -2.29 c/kWh. So for our household, a pure spot price contract will be cheaper unless the current mess in the World evolves to WW III and the prices go crazy again.
For those new to the thread, the table above compares our energy bill to spot average energy price and below that to the local energy company energy price, which currently would be 8,79c/kWh. I use this price as reference for calculating the savings, as we used to buy energy from them before changing to spot price. Markus’ code is quite effective as we have been able to keep energy cost below average spot price for every month except July, when we used the least amount of energy of the whole year. I am honestly quite impressed by the performance of the solution.
Some background information that explains some of the consumption month values might be in order. Totally we heat 250m2 although the garage and basement are at lower temperatures. Besides the ground heating system we have a solar heating system, a solar electricity system with a battery and an electric car. If it gets very cold or the spot price is exceptionally high we can also heat with wood. As we also have a 2 000L heat storage and a 500L hotwater storage that can be heated with the ground heating pump we have modified the original code so that all our heating is done during the cheapest hours between 0.00 and 8.00.
During the time of the year when very little solar energy is available we charge the battery with the cheaper electricity during the night and use it from the battery during the day. The battery can provide the energy for the base consumption of the house and occasional use of the coffee machine and the microwave oven for almost the whole day Food making is often done with the woodfired stove.
The washing machine and dishwasher are both manually timed to the cheapest hours.
